Looking at the seeding system, Cambridge House were not expected to reach the last 16 in the Danske Bank Schools' Cup but that's exactly what they did to earn a home draw against Royal School Armagh.
Regent started very strongly with their Irish Schools out-half Robbie Johnston directing the play and helping his team to an eight point advantage.
Stuart Martin crossed for a try and Johnston kicked a penalty before the home team began to challenge. Their out-half Dean Millar made a couple of breaks but the passes went to ground.
Eventually, they did reduce the arrears before the interval when, following a lot of pressure and a kick into the corner, they won turnover ball and centre Sam Millar, a brother of the out-half, touched down and added the points.
The Ballymena side's next try was against the run of play. They won a scrum on their '22' and full-back Cane McIlroy made 30 metres.
Scrum-half Tom Wharry then triple side-stepped through the opposition to go in for the score of the afternoon which Millar converted.
Following an attack involving several phases, the home side was further rewarded with a Millar penalty to make it 17-8.
In the final couple of minutes, an infringement allowed Regent to kick to the corner and centre Martin ran in close to touch.
Delighted home coach John Nicholl said: "Regent were at least a stone heavier a man so we did exceptionally well considering there were only two Upper Sixth pupils on our team.
"We had a bad start and had a purple patch, but the tie could have gone either way."